Heat shields are used to protect combustor shells from high temperatures in the combustion chamber. They are typically cast from high temperature resistant materials due to their proximity to the combustion flame. Casting operations are not well suited for complex-shaped parts and as such several constrains must be respected in the design of a combustor dome heat shield. For instance, a heat shield could not be cast with a film cooling louver due to the required tight tolerances between the louver and the heat shield. Also several secondary shaping operations must be performed on the cast heat shield to obtain the final product. Drilling and other secondary shaping operations into high temperature cast materials lead to high tooling cost as wear rates of drills and other shaping tools requires frequent cutting tool re-shaping or replacement.
There is thus a need for further improvements in the manufacture of combustor heat shields.